Using the ALL_SOURCE view you can only see source you have been granted privilege on (procedures, functions and package specifications). Since no privileges are granted on the package body you will never be able to see package body source from other users via this view. What you need is for your DBA to grant you SELECT on the DBA_SOURCE view. This will allow you to see all the source for all the users. Obviously, if you are looking at Oracle supplied packages all you will see is the wrapped source.

Cheers